The present disclosure describes systems and techniques relating to storage devices, such as Two Dimensional Magnetic Recording (TDMR) storage devices.
Various mediums are used to create storage devices for use in computing systems. In magnetic-medium-based storage devices, data can be stored on circular, concentric tracks on a magnetic disk surface. A read-write head can retrieve and record data on a magnetic layer of a rotating disk as the head flies on a cushion of air over the disk surface. When retrieving data, magnetic field variations can be converted into an analog electrical signal, which can then be amplified and converted to a digital signal for signal processing.
To increase the amount data that is stored in magnetic recording systems, smaller amounts of the magnetic medium have been employed to store each respective bit of data by using a smaller read-write head and corresponding track pitch, and by reducing the size of guard bands on either side of each track. As the recording densities have increased, various error correction techniques have been employed to assist in reading back the bits of data. In addition, in order to increase recording densities still further, some have proposed Shingled Magnetic Recording (SMR) to shrink the track pitch still further and remove the guard bands between tracks, which allows more tracks to fit on the recording medium. In SMR, the tracks are written so that one track partially overlaps the previous track.
Further, some have also proposed Two Dimensional Magnetic Recording (TDMR) to use in conjunction with SMR. As the track pitch gets smaller in SMR, at some point the one dimensional (1D) codes and detectors will not be able to handle the Inter Track Interference (ITI) from tracks adjacent to the one being read. In a 1D channel, the ITI negatively impacts performance. But in a two dimensional (2D) channel, the ITI can potentially assist in making the bit decisions when reading data from a magnetic medium.